This invention is directed to liquid chromatography and is particularly concerned with protection of the liquid chromatography system during unattended operation from the presence of air and overpressure.
In liquid chromatography a liquid sample is passed by a flowing stream of liquid solvent or buffer (the mobile phase) through a column packed with particulate matter (the stationery phase). While passing through the column the various components in the sample separate from one another by adsorbing and desorbing from the stationery phase at different rates such that these individual components elute from the column at different times. The separated components then flow through a detector which responds to each component both qualitatively and quantitatively, providing the user with the ability to achieve a separation and therefore to purify one or more of the constituents of the sample.
In liquid chromatography it is important to protect the particulate matter or chromatography media from overpressurization especially where the media is a gel. Overpressurization will crush the media which will lose its ability to process the liquid sample.
Additionally it is important to prevent air from entering the chromatography column because air will interfere with the liquid sample from reaching active sites in the chromatography media. The presence of air establishes air pockets within the column blocking even flow of the liquid sample through the column. Accordingly overpressurization and the presence of air substantially interfere with proper resolution of a liquid sample in the chromatography system and therefore will increase the cost of purifying the sample.
Similarly, other critical conditions may arise that threaten the continued performance of the chromatography column or the constituents of the fluid passing through it. These conditions include, but are not necessarily limited to, conditions of temperature, pH or conductivity.